ACT's ticket to Parliament, Epsom candidate John Banks, and the party's president have both rejected leader Don Brash's cannabis stance.

In a speech on law and order to party supporters in Auckland yesterday, Brash said he had serious questions about New Zealand's current marijuana laws and gave his personal endorsement to at least a debate over cannabis law reform.

However ACT president Chris Simmons today said decriminalising the class-C drug wouldn't be the party's policy next year, in 2014 or even 2017.

Simmons said the party's board wouldn't support decriminalisation, which was a "step too far." But he said it was important for party members to be asking questions and raising new ideas.

John Banks, the party's Epsom candidate and a former police minister, today said he could not support cannabis decriminalisation.

The party is polling well below the 5 per cent threshold to be guaranteed seats in Parliament, and is expected to depend on Banks winning Epsom.

This weekend also brought the shock resignation of parliamentary leader John Boscawen. Boscawen insisted he wasn't quitting over Brash's speech, but because he wanted to spend more time with his family. He made his decision on Friday.

He said his ''personal views'' on drug law reform weren't important but the issue should be debated, especially the $100m cost to the taxpayer of enforcing the laws. Decriminalisation wasn't ACT policy, he stressed.

Simmons said Boscawen's resignation was a ''total surprise."

The party will decide next week how to fill the gap on the list, but it was most likely candidates would just move up a place.

A mystery candidate in the number three spot was still to be confirmed, although it was widely assumed to be former president Catherine Isaac.

Labour leader Phil Goff said Brash is "a bit old to be a hippy".

Goff did not support decriminalisation, but said locking people up for using marijuana is "going far too far".

"But, nor do I believe it's a good thing to make cannabis more widely available.

"We know the impact it has on people's health, we know the impact it has on young people's development and we know the impact it has particularly on mental health where there are pre-existing problems.

"I think all of those are a strong case against allowing cannabis to more widely available."

Asked if he ever tried the drug, Goff replied: " I've never been a smoker of tobacco or other products, but I was a student in the 1970s.

"That's as far as I've ever said and I don't think that should become an issue."

Prime Minister John Key today labelled Brash's new-found support of decriminalising cannabis as a "step in the wrong direction".

Key criticised Brash for suggesting the law be changed because people were already breaking it by smoking dope.

"Go and ask the police officers, go and ask the parents in New Zealand whether they want their 18-year-old child to be smoking a joint before they head off to school," he told TVNZ's Breakfast programme.

"The message that Parliament sends has to be the right one and that is there is no place for drugs in our society.

"That is the thing that leads to criminal activity, it leads to brains being fried, it is a drug that takes them on to other drugs."

Brash has pointed to the $100 million cost to taxpayers of enforcing marijuana prohibition, saying many people believed it to be less dangerous than tobacco or alcohol.

But Key said police took a responsible view towards enforcing the law.

"They don't necessarily arrest everybody on Saturday night they catch with marijuana, the issue is whether that person is trading that drug, or any other drug and any other factors."

Brash this morning defended his comments, denying they were a political stunt aimed at raising ACT's poll ratings.

"Many people around the world are raising questions about the current policy towards marijuana," he told Radio New Zealand.

Decriminalising marijuana was not official ACT policy at this stage and Brash admitted its Epsom candidate and former police minister John Banks may not support his ideas, which could become a conscious issue for the party.

"I don't use it, don't intend to use it and hope none of my family ever use it either, but what we know is that cannabis use in New Zealand is one of the highest in the world, it's estimated to be three times the cannabis use in the Netherlands where it has been legal to use since 1976.

"In Australia some states have legalised it, some have not, consumption in those states seems to be falling."

Brash's speech followed the surprise resignation of ACT's deputy leader John Boscawen on Saturday.

Brash yesterday laughed off suggestions his speech had influenced Boscawen's decision to quit politics after the election.

Boscawen is to remain ACT's candidate for the Auckland electorate of Tamaki.

His departure puts ACT in the unusual position of having no MPs seeking re-election.

Brash said today he didn't accept the ACT brand was in danger of being obliterated, despite the party registering just 1.1 per cent support in the last Fairfax Media Research International Poll.

"Most of the people on our candidate list have a long association with the ACT Party and are very firmly committed to its values."

However, he conceded ACT was having a "clean out".

Boscawen this morning admitted the polls were bad for ACT but said he was confident Banks would win Epsom and the party would be returned to Parliament.

He aimed to boost ACT's party vote in Tamaki and would also be recruiting volunteers and members, Boscawen told Radio New Zealand.